A173107 Partial sums of abundant numbers (A005101).

12, 30, 50, 74, 104, 140, 180, 222, 270, 324, 380, 440, 506, 576, 648, 726, 806, 890, 978, 1068, 1164, 1264, 1366, 1470, 1578, 1690, 1804, 1924, 2050, 2182, 2320, 2460, 2604, 2754, 2910, 3070, 3232, 3400, 3574, 3750, 3930, 4116, 4308, 4504, 4702, 4902

Offset

1,1

Comments

The first odd term is a(232)=112223, which is also prime.

The square terms begin: 324, 576, 17424, 1841449, ...

Links

Michel Marcus, Table of n, a(n) for n = 1..10000

Formula

a(n) ~ c * n^2, where c = 1/(2*A302991) = 2.0192... - Amiram Eldar, Oct 21 2020

Mathematica

abQ[n_]:=DivisorSigma[1, n]>2n; Accumulate[Select[Range[200], abQ]]  (* Harvey P. Dale, Jan 27 2011 *)

Crossrefs

Cf. A000005, A005101, A173106, A302991.

Sequence in context: A125582 A031107 A019557 * A277978 A131874 A111396

Adjacent sequences: A173104 A173105 A173106 * A173108 A173109 A173110

Keyword

easy,nonn

Author

Jonathan Vos Post, Feb 09 2010

Extensions

Erroneous a(7) term corrected by Jason G. Wurtzel, Aug 12 2010

Status

approved